Dynamic testing of cast-in-place piles

This report presents the results of dynamic testing of two 21-in. (20-in. nominal) diameter Franki piles 44 and 55.5 ft long measured to the top of the bulb. The longer pile had a built-in fault, which was a reduction of the cross-sectional area by 50 per cent over a 2-ft length, the middle of which was located approximately 15 ft above the bulb. A central axial impact was imparted to the piles, as described in Report No. 376, from a 108-lb mass falling freely through 2 ft. Comparison of the response of the two piles provides a basis for judging the sensitivity of this method of detecting faulty piles.Peer reviewed: NoNRC publication: Ye